In this paper the thermodynamic analysis of equilibrium concentration of defects for the system BiFeO3(solid)‐O2 (gas) is carried out. The analysis is performed by the Kroger method of quasi‐chemical equations. The concentration of defects and free carriers vs. oxygen partial pressure in surrounding atmosphere at definite temperature are obtained. The calculations were carried out for 3 nm BiFeO3 nanowires too. When the defects ionization energies and material band gap are increased in nanowires, the picture of defects thermodynamics is changed. In 3 nm nanowire the area of self‐compensation is significantly broadened. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The problems of purification of quarry waters from the ions of heavy metals by the use of electrochemical method are considered and a construction of electrochemical reactor is described allowing to perform the so-called channel electrolysis at a high rate of liquid flow along of the electrodes in the conditions of limiting cathode current density (Jk). Technological schemes of complex processing of quarry waters for separation of useful components and estimation of their economic efficiency are presented. * Corresponding AuthorsTel:+995(032)2 3014 30 E-Mail: ts.gagnidze@mail.ru [a] I. Javakhisvili

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Abstract:A new technology for integrated processing of gold-bearing antimony ores has been developed in order to solve certain problems in the gold-mining industry. The technology based on vacuum-thermal processes allows not only extraction of gold but also production of associated materials-antimony sulfide (Sb 2 S 3 ) and metallic antimony (Sb). The paper presents theoretical as well as applied research. Kinetics of the process of antimony sulfide extraction from the ores was studied for different fractions. Optimal conditions for obtaining of Sb 2 S 3 were determined. The resulting product was a high-purity metallic Sb (~99.2 mass%). For extraction of gold from a cinder of vacuum-thermal processing of a concentrate, along with a thiourea method, the ecologically pure electrochemical method of our elaboration has been used. The effect of main technological parameters on the process of electrochemical leaching of the residues has been studied in the presence of gold complex former-thiourea in chloride system and optimal conditions of leaching were established providing the gold extraction from gold-containing residues by 82-90% in the conditions of so-called "soft" oxidation without release of molecular chlorine at the anode and eco-contamination.